Method of producing lactones



of the following objects will be obtained. An object of hexanol-Z-acetic acid; Afurther object of invention Patented Jan. 17, 1956 United statesPatehm e 2,731,475

one molecule each of furfural, butadiene and water react I togethertoform a lactone having the formula 2,731,475 r H H H H METHODOF PRODUCING LAcroNEs j rt o /1-r John C. Pfillyer and Jamel T, Edmonds, In, Bartlesv ille, H47 02! 01th., assignors to Phillips Qetroleum Company, a cor- I I .poration of Delaware h 1 H. C O N0 Drawing. Application numbers, 1951,

Serial No. zssass i a This compound is a solid, crystalline material. The hydrogenation of this lactone is best carried out in the presence of a hydrogenation catalyst, by which term We mean to include any catalyst active in promoting the addition of free hydrogen to the unsaturated carbon to carbon linkage. Various well known hydrogenation catalysts are metals such as palladium, zirconium, nickel, cobalt, copper, thorium, iron, and the like. Metal hydrogenation catalysts such as those above named are generally applied in a finely divided state, and can be supported, if desired. Further known hydrogenation catalysts are molybdenum oxide, chromium oxide, copper chromite, and nickel chromite.

Temperatures for this hydrogenation step are generally in the range from60" F. to 300 R, preferred temperatures being generally Within the limits of 60 F. to 150 F. Above 300 F. undesirable side reactions occur, particularl. h dro enol sis, and furthermore, control of the relates to a process wherein the condensation product of g digfficuli butadiene a a L tfit b ir 19= Y In carrying out the hydrogenation step, the lactone steps f n W g; b material is preferably dissolved in an inert solvent. Al- P mvenuon 1s a process t the i though it is generally preferable to have the lactone reactsubstltuted and unsubstltuted hydrogenated lactones (ant completely dissolved in the selected solvent, complete 9 Claims. lemma-343.3)

This inventionrelates to a method of producing lactones. In one of its more specific aspects this invention relates to substituted and unsubstituted lactones of ciscyclohexanol-2-acetic acid. In another of its more spe- Icific aspects it relates to amethod of producing said lactones, In another of its more specific aspects this .invention' relates to a method forthe production of the lactone of cis-cyclohexanol-Z-actetic acid resulting from the condensation of butadiene, furfura'l and water.

By the various aspects of this invention, at least one this invention relates to a new and novel method of producing lactones of substitutedand unsubstituted cis-icyclo structur a1 formula solution is not an absolute requisite. It is often convenient I! R "h to employ a saturated solution of crystals in the inert H H solvent, the presence of any undissolved. crystals being \l/ x). immaterial, since undersuch conditions we have found R C QTOH them to be easily hydrogenated. Preferred solvents used in the hydrogenation step include cyclohexanol, dioXane, methanol, and ethanol.

I 1 In one embodiment, We conduct the hydrogenation step R o at a temperature above the melting point of the lactone H R starting material, i. e. in the range of about 28030.0 P.

where R is selected from the group i ti f and thereby eliminate the need for a solvent. However,

C235 C3H7 and 04H, not more than twDR groupsbcing for most accurate control of the hydrogenation reactlon,

alkyl to produce compounds having the structural formula prefer u the men sowent and operate wlthm the H an H preferred temperature range. r

\ i Hydrogenation pressure is necessarily sufliciently hlgh to R I maintain the solution of lactone in liquid phase at hydrogenation temperature. Generally, a pressure as high as from 20 to p. s. i. g. is preferred. However, when i i desired, an operating pressure as high as 800-1000 p. s. i. g.

R- C may be employed but at pressures above about 1000 p. s. i. g., the hydrogenation is difiicult to control, and ex- 5 tensive undesirable side reactions occur. R This hydrogenation step is more fully described in our 0 Other objects of the present invcntionwill 'be ap arent U. S. Patent No. 2,551,675, issued May 8, 1951, said to those skilled in the art upon rcadin'g thc accompanying patent covering the use of the butadiene, furfural, Water disclosure. condensation product under reaction conditions resulting In' accordance with one embodiment or our invention 00 in the production of adipic acid. In that patent we disclose the lactone of cis-cyclohexanol-Z-aotit: acid is produced a process wherein the hydrogenated lactone is subjected fromfurfural, by first condensing furfur'al withbutadiene to drastic oxidation. In the present invention ditferent and water to form a lactone and then by liydrogcnatinga oxidizing conditions are employed, this process resulting lactone soproducedfollowed bypxidationbf theh'ydro- K in the production of the lactone of cis-cYclohexanol-Z- genated lactone product. In"mis -condensationreacrienhs acetic acid.

I the like.

The mild oxidizing agent employed in the present invention is preferably an alkali metal dichromate in the presence of sulfuric or acetic acids. Propionic and butyric acids can also be used. When conditions of time and temperature are suitably controlled, such oxidizing 7 agents will result in the formation of the lactone of ciscyclohexanol-2-acetic acid. Stronger oxidation should be avoided in order to avoid undesirable side reactions such auve p A erature in article by Newman et a1. appearing in the Journal. of the American Chemical Society, volume 67,

as the formation of adipic acid and other more highly ratios reduce the yield and, with higher ratios, at least a portion of the desired lactone will be further oxidized to adipic acid.

The mixture of alkali metal dichromate and sulfuric acid in which the ratio of dichromate to acid is in the ratio of 1:1 to 1:10, preferably 1:13 to 1:2 on a weight basis can be employed. In this ratio, the quantity of sulfuric acid is given as 100 per cent H2804. The preferred ratio of water to the total weight of dichromate plus 100 per cent sulfuric acid will be in the range of 1:1 to 10:1 parts by weight. In some instances more water may be employed depending on other conditions. The reaction temperature is in the range of 150 F., preferably 60-125" F., and still more preferably less than 100 F.

'At lower temperatures the rate of oxidation is much slower, while at higher temperatures larger quantities of undesired by-products are usually formed. When eight to ten parts water are used temperatures in the higher ranges, say 130 F. to 150 F., are used, while with one to three parts water, temperatures of from 30 F. to 50 F. are preferred. A reaction time of l to 24 hours, preferably 2 to 8 hours, is employed. It is usually preferred 'within the ranges specified that 'a reaction time in the lower part of the range be employed with a reaction temperature in the upper part of the range and vice versa. It is also usually preferred to add theoxidizing mixture to the hydrogenated lactone in increments since an exothermic reactionis'involved. The rate of addition and cooling must be so adjusted; as to maintain the reaction temperature within the desired range. a

In another embodiment, the oxidation reaction is carried 7 out by employingan alkali metal dichromate in the presence of acetic acid as the reaction medium. In this case,

the ratio of dichromate to acid is preferably in the ratio of 1:1 to 1:10 on aweight basis.

Conventional recovery procedures can be employed such as extracting the product from the reaction mixture inan'organic liquid, separating the extract, drying, and removing the solvent by distillation.

One lactone which we have .made by the method of our invention is the same as has been describedin the litpages 233-237 (1945).

Our invention is illustrated by the following examples. The reactants, their proportions, and other specific ingredients are presented as being typical and should not be construed to limit the invention unduly.

Example I Forty-six grams of the hydrogenated lactone, CoHuOa, prepared according to our U. S. Patent 2,551,675, and 50 ml. water were placed in a 1-liter three-necked flask fitted with a stirrer, and a solution of 81.6 grams of hydrated sodium dichromate in grams of concentrated sulfuric acid with 200ml. water was added gradually over a period of 5 hours. The reacting mixture warmed up to 50 C. (122 F.) during addition of they oxidizing agent.

After addition of the sulfuric acid-sodium dichromate solution was completed, the reaction mixture was stirred for one hour and then extracted with benzene; The benzene solution was neutralized with sodium bicarbonate, filtered and dried over anhydrous sodium sulfate. The solution was distilled to remove the benzene and a fraction comprising 13.0 grams of a clear liquid, boiling at 124 C. under 8 mm. pressure was recovered. The compound had a refractive index at 20' c. (u of 1.4790 and a specific gravity (114 of 1.0912.

A'time-temperaturecooling curve. gave'a long flat at .12.8 C. The saponification equivalent'of this liquid was found to be 142. Carbon andhydrogen analysis of this the lactone of cis-cyclohexanol-2-acetic acid as reported by Newman. The comparison is made in the following table: I i

Data Reported by Newman et a1 Product of Example Boiling point 124 0. 8 mm.

1.477 1.4790. :14 1.0923. 1.0912. Melting point, C... 14.8 12.8.

Example II Twenty-two grams of the hydrogenated lactone Cantos, 100ml. water, 52.5 grams hydrated sodium dichromate, and -69 gramsof concentrated sulfuric acid were mixed at 32 F. This mitxure was allowed to stand 15 hours at 32 F. Following extraction with ether, 2-

grams of the lactone of cis-cyclohexanol-Z-acetic acid was recovered. At 2- mm; Hg pressure this material boiled at 92 C. to 93 C. r

Example III A mixture of thirty-five grams of the hydrogenated lactone CaHuOs, 100 ml. water and 81 grams'of concentrated sulfuric acid were cooled to 32 F. Fifty-nine grams of hydrated sodium dichromate and 100 ml. water were being maintained between 32 F. and 50 F. V

After 15 hours at this temperature, the mixture was extracted with ether and the ether extract washed with so dium bicarbonate solution and distilled-water. Following drying, 1.3 grams of the lactone of cis-cyclohexanol-2- acetic acid was-recovered. At 15 mm. Hg pressure this material boiled at C. to 137 C. i

The residue contained 0.5 gram of white, crystalline acidic material which melted at 65 C. to 69 C. This apparently is Z-ketocyclohexane acetic acid, the reported melting point of which is 72.6 C. to 74.0 C.

Thus, this invention discloses a new method for the pro- 5 duction of substituted and unsubstituted lactones of ciscyclohexanol-Z-acetic acid. The starting material for use in this process is obtained in an extractive distillation process employing furfural as a selective solvent in the recovery of butadiene from a butene-butadiene hydrocarbon mixture.

As many possible embodiments may be made of this invention without departing from the scope thereof, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not in a limiting sense.

We claim:

1. A method for the production of the lactone of a cis-cyclohexanol-2-acetic acid comprising oxidizing a compound of the formula where R is selected from the group consisting of H, CH3, CzHs, CaHv, and CH9, not more than two R groups being alkyl.

2. The method of claim 1 in which the acid is CHaCOOH.

3. The method of claim 1 in which the acid is H2804.

4. The method of claim 1 in which the: acid is used in an amount to give a dichromate-acid ratio of 1:1.3 to 1:2 parts by weight.

5. A method for the production of the lactone of ciscyclohexanol-2-acetic acid comprising oxidizing by an alkali metal dichromate present in not in excess of a mol/mol ratio in the presence of an acid selected from the group consisting of H2504 and monocarboxylic organic acids containing 2 to 4 carbon atoms in aqueous solution at a temperature of from 30 F. to 150 F., employing a reaction time of 1 to 24 hours, and recovering resultant CH: CH:

6. The process of claim 5 in which the ratio of dichromate to acid is in the range of 1:1 to 1:10 parts by weight based on 100 per cent H2804; and the ratio of water to total weight of dichromate and. 100 per cent H2504 is in the range of 1:1 to 10:1 parts by weight.

7. The process of claim 6 in which the dichromateacid ratio is 121.3 to 1:2, the oxidation is carried out at a temperature in a range from F. to 125 F. and a reaction time of two to eight hours is employed.

8. The process of claim 7 in which the oxidation is carried out at a temperature of above 60 F. and below F.

9. A method for the production of the lactone of ciscyclohexanol-Z-acetic acid comprising subjecting cis-3- hydroxy-3,4,4a,5,6,7,8,8a-octahydro-1,2-benzopyrone to oxidation in the presence of an acetic solution of an alkali metal dichromate, said dichromate being present in not in excess of a mol/mol ratio based on said cis-3-l1ydroxy-3,4,4a,5,6,7,8,8a-octahydro-1,2-benzopyrone, the temperature of said oxidation step being maintained below 100 F.; and recoveringthe lactone of cis-cyclohexanol- 2-acetic acid as a product of the process.

References Cited in the file of this patent UNITED STATES PATENTS 2,551,675 Hillyer et al. a- May 8, 1951 

1. A METHOD FOR THE PRODUCTION OF THE LACTONE OF A CIS-CYCLOHEXANOL-2-ACETIC ACID COMPRISING OXIDIZING A COMPOUND OF THE FORMUOLA 